CODEWITHSUNDEEP
c#bit-manipulation
smatter
smatter

Reputation: 29178

Converting from bitstring to integer

I need a function like

int GetIntegerFromBinaryString(string binary, int bitCount)

if binary = "01111111" and bitCount = 8, it should return 127

if binary = "10000000" and bitCount = 8, it should return -128

The numbers are stored in 2's complement form. How can I do it. Is there any built in functions that would help so that I needn't calculate manually.

Upvotes: 4

Views: 4232

Answers (2)

deepee1
deepee1

Reputation: 13196

here you go. 

    static int GetIntegerFromBinaryString(string binary, int bitCount)
    {
        if (binary.Length == bitCount && binary[0] == '1')
            return Convert.ToInt32(binary.PadLeft(32, '1'),2);
        else
            return Convert.ToInt32(binary,2);
    }

Convert it to the 2-s complement version of a 32 bit number, then simply let the Convert.ToInt32 method do it's magic.

Upvotes: 3

SAK
SAK

Reputation: 25418

Prepend the string with 0's or 1's to make up to the bitCount and do int number = Convert.ToInt16("11111111"+"10000000", 2);

Upvotes: 5

Related Questions